This proposal is concentrated on a high priority area for the success of reactor-scale fusion devices: the avoidance and suppression of runaway electrons (RE). High-current reactor-size tokamaks will be susceptible to conversion of the plasma current into a highly energetic RE beam during off-normal disruption events. Subsequent uncontrolled loss of a RE current would damage plasma facing components.Within this project we will focus on understanding RE beam formation in disruptions, with particular emphasis on the effect of material injection, the foreseen method for disruption mitigation. We will study the evolution of the RE distribution during the phase of rapid plasma cooling (thermal quench), where collisional nonlinearities, partial screening, radiation effects, and impurity dynamics will be included in a self-consistent calculation with the electric field evolution. Furthermore, based on numerical simulations with state-of-the-art Fokker-Planck solvers we will develop a reduced kinetic model for runaway dynamics, suitable for the longer current quench phase. Via coupling to transport and magnetohydrodynamic codes, it will allow for rapid exploration of the conditions under which RE beams can be suppressed. The modeling tool suite will be validated against experiments through synthetic diagnostics, and will be employed to evaluate methods for RE suppression or avoidance. This is essential to ensure the safety and reliable operation of future fusion devices.
Professor vid Chalmers, Fysik, Subatomär fysik och plasmafysik
Finansierar Chalmers deltagande under 2018–2021